We propose to assess the role of cell-mediated immunity and/or hypersensitivity in the induction of myocarditis by coxsackievirus B3 (CVB3) in inbred strains of mice. Soluble antigens extracted from heart tissues of CVB3-inoculated myocarditic mice will be examined for their role in attracting sensitized lymphoid cells into the heart and their role in exacerbating or protecting mice from CVB3-induced myocarditis. Adoptive and/or passive lymphoid cell transfer experiments will be performed using donor/recipient mouse combinations involving myyocarditic and amyocarditic variants of CVB3. Characterization of soluble mediators released by CVB3-sensitized lymphoid cells and their capacity to recruit lymphoid cells into normal mouse heart tissue will be examined. The role of LiCl in abrogating CVB3-induction of myocarditis will be examined, along with studies of CVB3-induction of myocarditis in nude mice. Biochemical methods such as ion-exchange chromatography, salt fractionation and two-dimensional polyacrylamide gel electrophoresis will be used to isolate and characterize the new protein(s) induced by CVB3 in murine heart tissues in vivo to which sensitized lymphocytes respond and produce myocarditis. Purified virus particles of amyocarditic and myocarditic variants of CVB3 will be comparatively examined for markers co-variant with loss of capacity for induction of myocarditis by several methods: two-dimensional polyacrylamide gel electrophoresis analyses of capsid polypeptides, oligonucleotide fingerprint mapping of ribonuclease T1-digests of genomic RNA and analyses of polypeptides produced by in vitro translation of genomic RNA. We will investigate the limited replication of CVB3 in endothelial cells and the nonproductive interaction with myocytes in in vitro cultures. We will attempt to devise a method for detecting myocarditis in CVB3-inoculated mice without harm to the host, including a comparative analysis of plasma proteins by two-dimensional electrophoresis in polyacrylamide gels and assay of plasma for heart-specific enzymes. Administration of sex hormones and castration will be used in an attempt to study the role of sex differences in increased susceptibility of males to CVB3-induction of myocarditis.